The third avalanche narrowly missed them and they were able to go back and dig Mr Drake out.

But, with more avalanches likely, the three realised that their position was increasingly precarious.

"It was unsafe to go in there and that's when we had to make the gut-wrenching decision to leave our eight friends and start walking off the mountain," he said.

"After we walked for 10 minutes or so, I contemplated going back.

"As I turned to look at the mountain, the whole thing came burying down ... so we decided our best bet was to keep walking."

Among those he was forced to abandon was Daniel Bjarnason, who had saved his life moments earlier by pulling him out of the snow after the first avalanche.

"It's hard," he said. "I replay it in my head all the time whether it was the right decision or not.

"All three of us talked it through and decided the best bet was to get out of the area and go for help."

They returned by helicopter to help rescuers pinpoint the spot where their friends were but it was too late and the other eight men were dead.

Their decision to leave their friends buried under the snow echoes the agonising choice made by the mountaineer Simon Yates to cut a rope on which his fellow climber Joe Simpson was hanging after falling during a disastrous attempt on Siula Grande in the Peruvian Andes.

Unable to hold on any longer, he knew that if he did not cut the rope they might both fall to their deaths.

Remarkably, Simpson survived and his journey is catalogued in his book Touching the Void, which was later made into a documentary film.